Handle IOBoard VPD for Barreleye

Due to changes to the IOBoard VPD for Barreleye to include the MAC
address, the fru parser needs hardening to handle these changes.
First do not try to read data if the area length is 0. Second
adjust the area length as the checksum is now at a 4 byte
boundary instead of 8. Add a new argument to phosphor-read-eeprom
to activate this handling.
Fixes openbmc/ipmi-fru-parser#19

Change-Id: I8f47205712f1f4be43e1c14359070f27e7f704b8
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
5 files changed